“May cause drowsiness”: melatonin found in wine grapes

It’s no surprise that red wine makes you sleepy, but Italian scientists have discovered the reason - high levels of the sleep hormone melatonin.

According to University of Milan lead researcher Iriti Marcello, the melatonin content in wine grapes could help regulate human sleep-wake patterns, known as the circadian rhythm, just like the melatonin produced by the pineal gland in mammals.

Melatonin, which is believed to have antioxidant properties, is naturally secreted by the brain’s light-sensitive pineal gland at night, and informs the body when it is time to sleep.

Traditionally, melatonin was thought to be produced exclusively by mammals, but it has recently been discovered in plants.

The scientists found high levels of melatonin in the Nebbiolo, Merlot, Cabernet Savignon, Sangiovesse and Croatina grape varieties.

The team claims that melatonin content can be enhanced in grapes by treating vines with a plant vaccine called Benzothiadiazole, a chemical that increases disease resistance in plants.

The research will be published in the Journal of the Science of Food and Agriculture, but has been met with some scepticism by other boffins, including Richard Wurtman of the brain and cognitive science department at MIT.

Wurtman told Chemistry & Industry magazine that further research is needed to determine whether the compounds discovered are melatonin, or something very similar.